After the establishment of the republican regime, a decree of the Constituent National Assembly dated June 19, 1911, published in the Government Gazette No. 141 of the same year, it approved the National Flag which replaced the Flag of the Constitutional Monarchy. This decree had its proper regulations, published in the Government Gazette No. 150 (Decree of 30 June).

TheNational Flagis divided vertically into two basic colors, dark green and scarlet, getting the green side of the junk. The center, and superimposed on the union of colors, has the national coat-of arms, edged in white and seated on the Manueline armillary sphere, yellow and black revived.

The length of the flag is and a half times the height of the hoist. The division between the two basic colors should be made ​​so that they are two-fifths of the total length occupied by the green and the remaining three-fifths the red. The central emblem occupies half the height of the hoist, being equidistant from the top and bottom edges.

The choice of colors and the flag of the composition was not peaceful and has given rise to controversies on and the presentation of various proposals. Prevailed constant explanation of the report submitted by the Commission then appointed by the government which, in an opinion heraldically not always correct, tried to express an eminently patriotic way this National Symbol.

Thus, according to the Commission, the white is "a beautiful fraternal color, where all other merge, color simplicity, harmony and peace" and under it, "dotted the corners (...) if the hurt the 1st stiff battles for Portuguese nationality (...). Then it's the same white color, revived enthusiasm and faith by the Red Cross of Christ marks the epic cycle of our maritime discoveries. "

Red, defended the Commission, "it must rank as one of the basic colors to be color combative, hot, virile, par excellence. It is the color of conquest and laughter. A singing color, burning, cheerful (...) . Remember the blood and incites victory. "

Regarding the green color of hope, the Commission could hardly justify their inclusion in the Flag. In fact, it is a color that had no historical tradition, having been fetched an explanation for her in the preparation and Revolt of consecration of January 31, 1891, from which green will come up in the "decisive moment, under the inflamed reverberation of the revolutionary flag, the Portuguese people did sizzle the redeeming flash of dawn. "

Once the colors defined, the Commission was concerned to determine the most representative emblems of the nation for inclusion in the Flag.

Regarding the armillary sphere, which had been adopted as a personal emblem of King Manuel I, being since then always present in the national flagship, it enshrines "the Portuguese maritime epic (...) done culminating essential of our collective life."

Turn on the armillary sphere understood the Commission to base the white shield with the machines, perpetuating and consecrating so "human miracle of positive bravery, tenacity, diplomacy and audacity that could bind the first links of social and political affirmation of the Portuguese nationality ".

Finally, the Commission found "must surround the white shell of the machines by a wide crimson band, with seven castles", considering these symbol "more energetic integrity and national independence."